1. Field of the Invention
The present invention generally relates to the field of bar feeders. More particularly, the present invention relates to the field of automatic pneumatic bar feeders for automatically feeding a plurality of bar stocks to a computer numerical control (CNC) machine or the like device.
2. Description of the Prior Art
Specifically, prior art feeding devices include an elongated bar support tube for receiving a length of bar stock and a pusher feed mechanism which is movable along the interior of the support tube, to feed the bar stock to a CNC machine or the like.
The following ten (10) prior art patents are found to be pertinent to the field of the present invention:
1. U.S. Pat. No. 3,760,661 issued to Eichenhofer on Sep. 25, 1973 for "Pneumatic Bar Feeder Control For Multiple Spindle Screw Machines" (hereafter "the '661 Eichenhofer Patent");
2. U.S. Pat. No. 3,780,924 issued to Eichenhofer on Dec. 25, 1973 for "Automatic Bar Feeder Attachment For Multiple Spindle Screw Machines" (hereafter "the '924 Eichenhofer Patent");
3. U.S. Pat. No. 3,823,628 issued to Fortune on Jul. 16, 1974 for "Raw Material Feeder System"(hereafter the "Fortune Patent");
4. U.S. Pat. No. 3,894,452 issued to Kazik et al. on Jul. 15, 1975 for "Control Arrangement For Multi-Spindle Automatic Screw Machine And The Like" (hereafter the "Kazik Patent");
5. U.S. Pat. No. 3,937,331 issued to Spercel on Feb. 10, 1976 for "Bar Stock Loader And Feed Mechanisms" (hereafter the "Spercel Patent");
6. U.S. Pat. No. 4,088,230 issued to Doe et al. on May 9, 1978 for "Control Means For A Bar Holder And Feeder Coupled To An Automatic Machine Tool" (hereafter the "Doe Patent");
7. U.S. Pat. No. 4,413,939 issued to Peris on Nov. 8, 1983 for "Bar Stock Feeder" (hereafter the "Peris Patent");
8. U.S. Pat. No. 4,423,993 issued to Eaton on Jan. 3, 1984 for "Retractable Bar Stock Feeder" (hereafter the "Eaton Patent");
9. U.S. Pat. No. 4,766,788 issued to Yashiki et al. on Aug. 30, 1988 for "Superprecision Lathe" (hereafter the "Yashiki Patent"); and
10. U.S. Pat. No. 5,881,617 issued to Cucchi on Mar. 16, 1999 for "Bar Feeder For Multi-Spindle Lathes, With Selective Drive" (hereafter the "Cucchi Patent").
The '661 Eichenhofer Patent discloses a pneumatic bar feeder control for multiple spindle screw machines. It comprises a drive roller bar feed moved by a cam system for engaging and advancing a bar during the feed cycle of the machine. The control system includes a stop to be engaged by the bar in an overfeed position, and a pneumatic cylinder for pushing the bar back from the overfeed position to a feed position. The pneumatic cylinder is controlled by an air valve operated by a cam follower moved by a surface of the cam means for a predetermined timed relation of the air valve with the movement with the driver roller.
The '924 Eichenhofer Patent discloses an automatic bar feeder attachment for multiple spindle screw machines. It comprises a drive motor which is mounted in a housing, with one end of the housing formed as a journal for journal mounting upon a support shaft forming part of the spindle machine. A drive roller is mounted upon the opposite end of the housing and driven constantly by a motor shaft. The roller is mounted upon an outer shaft which fits over and is secured to the motor shaft and which forms part of a cover which overlaps the housing and which is supported by bearings, thereby transmitting the transverse forces applied to the roller directly to the housing rather than solely to the motor shaft.
The Fortune Patent discloses a raw material feeder system for automatically feeding flexible stock. The feeder comprises an indexing drum which has a plurality of peripherally disposed, hollow tubes for housing raw stocks. Pneumatic pressure is used for periodically advancing each raw stock within the tubes into the automatic lathe for processing. When the work piece is finished, another portion of the stock is automatically advanced in the lathe.
The Kazik Patent discloses a control arrangement for multi-spindle automatic screw machine and the like. It comprises a rotary timing member which is driven by a motor via a gear arrangement with different speeds for work feeding and for quick-traverse movements.
The Spercel Patent discloses a bar stock loader and feed mechanisms. The loader mechanism is used with a machine tool having a chuck which is operated between opened and closed conditions. The bar feed mechanism has a feed gripper which is also opened and closed. The loader mechanism is operable to transfer one piece of bar stock at a time from an intermediate station to a loading station while simultaneously transferring another piece of bar stock from a magazine to the intermediate station. After the piece of bar stock has been moved to the loading station, the piece of bar stock is registered relative to the feed gripper and chuck by activating a compensating cylinder to press the leading end of the piece of bar stock against a stop member. When the stop member has been moved out of the way of the registered piece of bar stock, a main cylinder is activated to push the registered piece of bar stock into the open feed gripper and chuck.
The Doe Patent discloses a control means for a bar holder and feeder coupled to an automatic machine tool. The control means comprises counting means settable to a determined number, trip means operable when in a set position to trip the counting means once for each work piece machined, trigger means effective to move the trip means to the set position when a new length of bar is fed into the bar holder, and coupling means coupling the counting means to means controlling machining operation of the machine tool. The determined number is settable so that after a number of workpieces equal to the determined number have been machined from a length of bar preceding the new length of bar. The machine is stopped if the remnant of the length of bar is not of sufficient length to safely permit machining of a further workpiece.
The Peris Patent discloses a bar stock feeder which has both horizontal and vertical adjustment of the carrier standards and a quick acting locking and pneumatic connecting assembly for engaging the bar stock tube assembly which is supported and aligned on the standard by a retainer assembly.
The Eaton Patent discloses a retractable bar stock feeder. It has a pneumatic circuit with positive feed and vacuum circuits. The feeder uses an air pump to provide vacuum from a pressure line and is mounted within a single base pedestal to present a readily operable control panel. The feeder manually loads a stock of bar material.
The Yashiki Patent discloses a super precision lathe which has a main spindle mounted at one end of a vacuum chuck rotatably supported in an air bearing fixed on a head stock. The main spindle has a first vacuum passage connected to the vacuum chuck and is opened at the outer surface of the main spindle, a second vacuum passage formed in the head stock and of which an open end is connected to a vacuum pump and which is opened at the inner surface of the air bearing. The first vacuum passage connects the second vacuum passage through an interconnection region defined by two annular grooves formed at opposite positions of the outer surface of the main spindle and the inner surface of the air bearing.
The Cucchi Patent discloses a bar feeder for multi-spindle lathes, with selective drive. It comprises a rotating drum with a plurality of guides for the bars, which longitudinally extend in different angular positions on the outer surface of the drum. Bar pushing members are slidably arranged at one end and are supported to rotate coplanarly with the drum around a central pinion gear connected to a drive motor. This is more of a mechanical bar feeder.
It is highly desirable to have a very efficient and also very effective design and construction of a pneumatic bar feeding apparatus for automatically feeding a plurality of bar stocks to a CNC machine or the like device, thereby eliminating the need to reload the bar feeding apparatus with another bar stock one at a time. It is desirable to provide a pneumatic bar feeding apparatus that is not noisy and does not vibrate, and is maintenance free. It is also desirable to provide a pneumatic bar feeding apparatus that allows for fast production with no wasted material.